The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.
A hybrid vehicle is a vehicle using two or more different kinds of power sources, and is generally a vehicle that is driven by an engine that obtains a driving torque by burning fuel and a motor that obtains a driving torque with battery power.
Hybrid electric vehicles can be provided with optimum output torque, depending on how the engine and the motor are operated while the vehicles are driven by the two power sources, that is, the engine and the motor.
Hybrid electric vehicles may form various structures using the engine and the motor as power sources, and hybrid electric vehicles are classified as a TMED (Transmission Mounted Electric Device) type, in which the engine and the motor are connected by an engine clutch and the motor is connected to the transmission, and an FMED (Flywheel Mounted Electric Device) type, in which the motor is directly connected to a crankshaft of the engine and connected to the transmission through a flywheel.
From among these, since the FMED type of the hybrid electric vehicle is very noisy and has severe vibration, vibration reduction thereof is being studied. A method of frequency analysis which extracts the vibration component is normally used for this.
An analog method using a band pass filter has been used in a conventional frequency analysis, and the analog method of analysis determines whether or not a frequency is abnormal based on an amplitude of each expected point of a frequency band.
However, distinguishing between the vibration component of the engine and the vibration of the noise component is difficult, and unnecessary over-control of the vibration negatively affects control efficiency and energy management. Further, because it is only possible to create and synchronize a reference signal with respect to a specific frequency in the conventional frequency analysis, comprehensive and active control of other frequencies which may be additionally generated is not performed.